In unmagnetized materials the domains are randomly aligned in different directions and cancel each other out. In a magnet all the domains are oriented in the same direction. In the case of a nail, the domains can be aligned in the same direction causing the nail to become magnetic.
Answer:
a) Focal length of the lens is 8 cm which is a convex lens
b) 6 cm
c) The lens is a convex lens and produces a virtual image which is upright and two times larger than the object.
Explanation:
u = Object distance = 4 cm
v = Image distance = -8 cm
f = Focal length
Lens Equation

a) Focal length of the lens is 8 cm which is a convex lens
Magnification

b) Height of image is 2×3 = 6 cm
Since magnification is positive the image upright
c) The lens is a convex lens and produces a virtual image which is upright and two times larger than the object.
Answer: 0.98m
Explanation:
P = -74 mm Hg = 9605 Pa = 9709N/m^2
= 9605 kg m/s^2/m^2
density of water: rho = 1 g/cc = 1 (10^-3 kg)/(10^-2 m)^-3 = 1000 kg/m^3
Pressure equation: P = rho g h
h = P/(rho g)
h = (9605 kg/m/s^2) / (1000 kg/m^3) / (9.8 m/s^2)
h = 0.98 m
0.98m is the maximum depth he could have been.
Answer:

Explanation:
first write the newtons second law:
F
=δma
Applying bernoulli,s equation as follows:
∑
Where,
is the pressure change across the streamline and
is the fluid particle velocity
substitute
for {tex]γ[/tex] and
for 

integrating the above equation using limits 1 and 2.

there the bernoulli equation for this flow is 
note:
=density(ρ) in some parts and change(δ) in other parts of this equation. it just doesn't show up as that in formular